Backup and recovery software products are crucial for enterprise level network clients. Customers rely on backup systems to efficiently back up and recover data in the event of user error, data loss, system outages, hardware failure, or other catastrophic events to allow business applications to remain in service or quickly come back up to service after a failure condition or an outage. Data protection and comprehensive backup and disaster recovery (DR) procedures become even more important as enterprise level networks grow and support mission critical applications and data for customers. The advent of virtualization technology has led to the increased use of virtual machines as data storage targets. Virtual machine (VM) disaster recovery systems using hypervisor platforms, such as vSphere from VMware or Hyper-V from Microsoft, among others, have been developed to provide recovery from multiple disaster scenarios including total site loss.
With regard to enterprise data stored in databases, a database engine typically performs modifications to database pages in memory (such as in a buffer cache, as opposed to writing the pages to disk after every change. The engine periodically issues a checkpoint on each database that writes the current in-memory modified pages and transaction log information from memory to disk. Database management systems thus typically follow a checkpoint mechanism wherein transaction logs are maintained that contain the history of actions executed by the database engine. This helps to guarantee ACID (atomicity, consistency, isolation, and durability) properties of database management systems to allow safe sharing of data and provide protection from crashes or hardware failures.
Transaction logs generally comprise files that list changes to the database and that are stored in a stable storage format. Any backup solution dealing with database backups would essentially need to backup both the database file and the transaction logs in order to recover it during a catastrophe. The recover process would involve recovering the database file and replaying the logs until the checkpoint is reached to get the database to a previous desired consistent state. However, this process of recovery is associated with certain challenges, such as the need to maintain multiple log files along with the database file during each backup operation, and identifying which logs to replay for a particular recovery/restore operation. This last task is generally not trivial and requires intimate knowledge of the database and its associated tools to find the correct log file set for a particular operation.
What is needed, therefore, is a database management and recovery system that eliminates the need to maintain transaction logs as part of database savesets at each level. There is a further need to reduce the amount of data stored and reduce the recovery time associated with finding and replaying the appropriate transaction logs.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions. EMC, Data Domain, Data Domain Restorer, and Data Domain Boost are trademarks of EMC Corporation.